Spinneret assembly

ABSTRACT

A spinneret assembly for melt spinning bicomponent filaments is provided. A spinning block couples a spinneret plate, a distributor plate, and a dual reservoir plate in operative spinning relation. Grooves extend radially from a central concavity at the interface of spinneret plate and the distributor plate and at the interface of the distributor plate and dual reservoir.

Unlted States Patent 1 1 1 1 3,730,662

Nunning 1 1 May 1, 1973 5 SPINNERET ASSEMBLY 3,038,236 6/1962 Breen ..264/171 X 3,262,153 7/1966 Mercer et a1 ..425/463 lnvemorr Walter Nunnmg, Pensacola, 3,315,021 4/1967 Luzzato 264/171 x 3,320,633 5/1967 Canzio ...425/463 [73] Asslgnee' Company 3,350,741 1 1 /l967 Yoshida et a1... ..425/463 22 Filed; 1 1971 3,538,544 11/1970 Ullman ..425/l31 APP], NO-I 203,895 Primary Examiner-.l. Spencer Overholser Related US. Application Data Continuation of Ser. No. 886,194, Dec. 18, 1969, abandoned.

US. Cl. ..425/13l, 264/171, 425/463 Int. Cl. ..B29f 3/12 Field of Search ..425/131133, 462-464;

References Cited UNITED STATES PATENTS 4/1946 Taylor et a1. ..425/463 Assistant Examiner-Michael 01 Sutton Attorney-Ke1ly O. Corley [57] ABSTRACT A spinneret assembly for melt spinning bicomponent filaments is provided. A spinning block couples a spinneret plate, a distributor plate, and a dual reservoir plate in operative spinning relation. Grooves extend radially from a central concavity at the interface of spinneret plate and the distributor plate and at the interface of the distributor plate and dual reservoir.

3 Claims, 4 Drawing Figures Patented May 1, 1973 3,730,662

2 sheet -s 1 r4 l I w \&%

FIG. I.

NVENTOR,

WALTER J. NUNNING.

ATTORNEY Patented May 1, 1973 3,730,662

2 Sheets-Sheet 2 FIG. 4.

INVENTOR WALTER J. NUNNING' 7 BY 1% m.

ATTORNEY SPINNERET ASSEMBLY This is a continuation of US. Pat. application Ser. No. 886,194, filed Dec. 18, 1969, and now abandoned.

BACKGROUND OF THE INVENTION For many years it has been known to make textile filaments through the conjugation of two or more polymeric materials having quite dissimilar shrinkage or heat retraction characteristics. The fusion of the two substances is accomplished by bringing them together in a spinneret assembly without intimate mixing so that the substances adhere to each other along the length thereof to form a continuous linear interface. This is known as a side-by-side arrangement and the filaments are potentially crimpable. The crimp is developed after the filaments have been drawn and relaxed; and the crimp takes the form of a non-torque, randomly reversed helix. The arrangement of the two substances may also take the form of a sheath-core. If the core is eccentrically arranged, the filaments will likewise crimp.

Various constructions of spinneret devices have been proposed. The priorart devices have not been entirely satisfactory, particularly when it' is desired to conjugate polymeric substances of high viscosities encountered in melt spinning. One of the most severe drawbacks of the prior art devices is the lack of uniformity in the delivery of the components when a plurality of filaments are produced using a single spinneret assembly. For a sideby-side bicomponent filament, it is common to use onehalf of one component and one-half of the other component. However, as a practical matter in producing multifilament yarn the percentages of the components may vary considerably from one filament to another in a threadline. This gives rise to product non-uniformities and such faults should be avoided. Spinneret assemblies of the prior art are also complex in construction; and, accordingly, they are expensive to manufacture.

The present invention provides an improved spine neret assembly that is simple and inexpensive in construction and provides substantial equal thermal histories for the components moving therethrough. By using it, one is able to minimize variations in component distribution and thermal history when a multifilament side-by-side or sheath-core bicomponent yarn is produced by melt spinning techniques.

SUMMARY OF THE INVENTION According to the present invention there is provided a spinneret assembly for melt spinning sideby-side or sheath-core bicomponent multi-filament yarn with excellent uniformity in component distribution from filament to filament. This is accomplished by employing a spinning block which couples a spinneret plate, a distributor plate and a plural reservoir plate of particular construction. The spinneret plate has a melt delivery face and a melt extrusion face. At least one pair of polymer conveying capillaries extends from the melt delivery face and converge to the point of polymer conjugation and thence extends as a single capillary to the melt extrusion face to form an extrusion orifice. The distributor plate is contiguous with the melt delivery face of the spinneret plate and has an upper face and a lower face. At the upper and lower faces centrally disposed concavities for conveying supplies of different molten polymer compositions are provided. At least one groove radially extends from. the concavity at the upper face. Passageways extend from the upper grooves to one of the pair of converging capillaries. At least one groove radially extends from the central concavity at the lower face and communicates with the other of the pair of converging capillaries. The polymer reservoir plate is contiguous with the upper face of the distributor plate and has a pair of separate reservoirs for molten polymer. A passage is provided for flowing polymer from one reservoir to the central concavity at the upper face. Another passage is provided for flowing a different polymer from the other reservoir through the distributor plate to the central concavity at the lower face.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a central longitudinal section of the spinneret assembly of the present invention.

FIG. 2 is a top plan view of the distributor plate wherein the passage for polymer delivery to the central concavity is shown in phantom.

FIG. 3 is a bottom plan view of the distributor plate wherein the passage for polymer delivery to the central concavity is shown, partly in phantom. I

FIG. 4 is an exploded perspective View of the disclike elements normally coupled to form the preferred embodiment of the spinneret assembly of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is now made to the drawing and particularly to FIG. 1 thereof wherein an. assembled sectional view of the assembly is given. The spinneret plate 1 is illustrated as two contiguous discs la and 1b. Two separable superimposed discs as shown are preferred in order to facilitate the cutting of the capillaries particularly where a reduction in diameter of the capillary near the point of polymer extrusion is desired. Such a reduction is normally desirable and is illustrated in the drawing. t r

The spinneret plate has a melt delivery face 2 and a melt extrusion face 3. Two capillaries 4' and 5 are shown in FIG. 1 wherein polymer conjugation is accomplished. Although ten such capillaries are shown in the full illustrated embodiment, any suitable number can be provided. The capillaries are bifurcated in their upper portions In operation dissimilar polymers flow downwardly through each branch and converge into single lamina] streams in the lower portion of the capillaries. The molten polymer streams emitted from the extrusion face are cooled to form multifilament yarn which may be further processed into textile articles and the like. The filament extruded from capillary 4 is a side-by-side conjugate filament. Within capillary 5 at the point of polymer confluence a nozzle is provided so that the flow of one polymer surrounds the flow of the other. The filament extruded from capillary 5 is a sheath-core conjugate filament.

The molten polymer distributor plate 6 is a disc-like member of substantially the same diameter as that of the spinneret plate and is contiguous and superimposed thereon. This plate has an upper face 7 and a lower face 8. In the upper face there is a central concavity 10; and in the lower face there is a central concavity 11. A plurality of grooves 12 radially extend from concavity 10. A plurality of grooves 13 radially extend from concavity 11. Near each of the ends of grooves 12 passageways 14 provide for polymer flow from the grooves to one of each pair of converging capillaries. Grooves 13 directly communicate with the others of the pair of converging capillaries.

The molten polymer reservoir plate 15 is also a disclike member of substantially the same diameter as that of the spinneret plate and is contiguous with and superimposed on the distributor plate 6. Plate 15 has two reservoirs 16 and 17 for retaining two dissimilar polymers delivered from separate melters (not shown) via conduits 18 and 20 in element 21. First passage 22 is provided for flowing polymer from reservoir 16 to upper concavity 10. Second passage 23 in plate 15 is provided for flowing polymer from reservoir 17 via passage 24 in plate 6 to lower concavity 11. As shown, passage 24 is diagonally disposed through the-distributor plate 6. It will be appreciated that concavities and 11 and grooves 12 and 13 are preferably milled in the upper and lower faces of plate 6. However, these concavities and grooves need only be at the interface of plates 1b and 6 and at the interface of plates 6 and 15. The concavities and grooves can be provided in part or entirely in the melt delivery face 2 and in the bottom surface of plate 15.

Coupling block 25 holds spinneret plate 1, the distributor plate 6 and the reservoir plate in operative spinning relation.

During spinning molten polymer A moves through conduit and reservoir 16. Therefrom, it moves through passage 22 into concavity 10 and outwardly along grooves 12. From a point near the end of the grooves polymer A moves downwardly through passage 14 and then through selected bifurcations of capillaries 4 and 5. On the other hand polymer B moves through conduit 18 and reservoir 17. Therefrom, it moves through connecting passages 23 and 24 into concavity 11 and outwardly along grooves 13. From a point near the end of these grooves polymer B moves through the remaining bifurcated path of capillaries 4 and 5. The polymers converge in the spinneret plate and flow in .side-by-side laminae or sheath-core form through extrusion orifices 26. As illustrated ten such orifices are provided in circumferential array.

A spinneret assembly as above described was constructed of stainless steel and was placed in spinning block maintained at 220C. Ten capillaries each with a diameter of mils were provided in the spinneret plate. Nylon-6 (polymeric aminocaproic acid) was supplied as a primary molten polymer and a thermoplastic polyester urethane elastomer was supplied to the assembly as a secondary molten polymer. The metering pump speeds were set to deliver melts in a ratio of I21 by volume at a spinning speed of 300 yards per minute. After filament formation, the ten bicomponent filaments were drawn 350 percent to a denier of about 25. The filaments were cross sectioned, and photomicrographs were made thereafter. It was noted that in each filament the two components were arranged hemispherically.

The present invention provides a spinning assembly where side-byside or sheath-core arrangement of comonents can be made with excellent distribution of the components from filament to filament within a multifilament threadline. The construction of the assembly is inexpensive and not complex. The spinneret assembly provides for substantially equal polymer residence time therein for each polymer to each filament since the separate paths from the reservoirs to the point of polymer adjoining are substantially equi-distant.

Other advantages will be noted.

I claim:

1. A spinneret assembly for melt spinning bicomponent filaments, comprising:

a. a spinneret plate having a melt delivery face and a melt extrusion face, said spinneret plate including a plurality of capillaries, said plurality being greater than two, each said capillary extending from a respective point of polymer confluence to said extrusion face to form an extrusion orifice;

. a polymer distribution plate having a lower face contiguous with and forming a first interface with said melt delivery face and having an upper face;

c. a third plate having a face contiguous with and forming a second interface with said upper face;

. means defining a first central concavity at said first interface;

e. means defining a second central concavity at said second interface;

f. means defining a like plurality of first polymer passages, each of said first polymer passages extending from said first concavity to a respective point of confluence;

g. means defining a like plurality of second polymer passages, each of said second polymer passages extending from said second concavity to a respective point of confluence;

h. a first polymer supply passageway for supplying a first polymer to saidfirst concavity;

i. a second polymer supply passageway for supplying a secondpolymer to'said second concavity;

j. the dimensions of said first polymer supply passageway, said first concavity, and said first polymer passages being selected to provide substantially equal polymer residence times from said first polymer supply passageway to said points of confluence; and s I k. a block coupling said spinneret plate, said distributor plate and said third plate in operative spinning relation.

2. The assembly defined in claim 1, wherein the dimensions of said second polymer supply passageway, said second concavity, and said second polymer passages are selected to provide substantially equal polymer residence times from said second polymer supply passageway to said points of confluence.

3. The assembly defined in claim 1, wherein said spinneret plate consists of two separable superimposed disc-like members with the point of capillary confluence being located in the member contiguous with said distributor plate. 

1. A spinneret assembly for melt spinning bicomponent filaments, comprising: a. a spinneret plate having a melt delivery face and a melt extrusion face, said spinneret plate including a plurality of capillaries, said plurality being greater than two, each said capillary extending from a respective point of polymer confluence to said extrusion face to form an extrusion orifice; b. a polymer distribution plate having a lower face contiguous with and forming a first interface with said melt delivery face and having an upper face; c. a third plate having a face contiguous with and forming a second interface with said upper face; d. means defining A first central concavity at said first interface; e. means defining a second central concavity at said second interface; f. means defining a like plurality of first polymer passages, each of said first polymer passages extending from said first concavity to a respective point of confluence; g. means defining a like plurality of second polymer passages, each of said second polymer passages extending from said second concavity to a respective point of confluence; h. a first polymer supply passageway for supplying a first polymer to said first concavity; i. a second polymer supply passageway for supplying a second polymer to said second concavity; j. the dimensions of said first polymer supply passageway, said first concavity, and said first polymer passages being selected to provide substantially equal polymer residence times from said first polymer supply passageway to said points of confluence; and k. a block coupling said spinneret plate, said distributor plate and said third plate in operative spinning relation.
 2. The assembly defined in claim 1, wherein the dimensions of said second polymer supply passageway, said second concavity, and said second polymer passages are selected to provide substantially equal polymer residence times from said second polymer supply passageway to said points of confluence.
 3. The assembly defined in claim 1, wherein said spinneret plate consists of two separable superimposed disc-like members with the point of capillary confluence being located in the member contiguous with said distributor plate. 